New systems designed to avoid chaotic scenes at Irish ports and airports in the event of a no-deal Brexit have not yet been trialled.
With only 37 days until the potential worst-case scenario, the plans have yet to be road-tested.
Dublin Port has a contingency plan, known as Operation Purge, which is designed to ensure minimum traffic congestion in the city if trucks get delayed by checks.
However, Fianna Fáil Brexit spokesperson Lisa Chambers claims the fact it and other contingency operations have not been trialled "is reckless".
"While I am told that arrangements will be tested prior to October 31, the reality is that there is very little time to address any problems that are identified or put mitigation measures in place.
"Only last week the chief executive of the Dublin Port Company, Eamonn O'Reilly, said that in the event of checks being applied, there is just 3km of roads within Dublin Port with the capacity for about 250 trucks and in my view there does not seem to be a rational plan in place to deal with potential delays at the port," the Mayo TD said.
She accused the Government of burying its head in the sand and hoping events will turn out OK.
"They need to assess the systems that have been put in place and if they are adequate in the event of a no-deal Brexit," she said.
Taoiseach Leo Varadkar did recently visit Dublin Port to view new inspection posts and storage units that have been built to facilitate customs checks.
In reply to a parliamentary questions about preparedness, Transport Minister Shane Ross said a variety of agencies are working to "ensure optimal goods trade traffic flows at our key ports and airports".
"The robustness of the proposed inter-agency arrangements will be tested prior to October 31, 2019, by the relevant agencies," he said.